Your Baby at Week 21

It’s week 21 and your little monkey is about the size of a medium banana — around 7 inches long and almost three-quarters of a pound. As he gets bigger and bigger, you’ll be able to feel those movements more and more…at least when he’s not hunkering down for one of his many naps. Naps? Yup. Though it may not feel like it with all the kicking and poking going on in there, your snoozer sleeps as much as 14 hours a day.

But not because it’s boring at Hotel Uterus. On the contrary: You keep things very interesting simply by switching up the catering menu. Those teensy taste buds on his tiny tongue are now developed enough so while he can’t actually eat the foods you do, he can taste them in the amniotic fluid.

And taste them he will as he gulps several ounces each day for hydration and nutrition…and to practice swallowing and digesting. So sup on something spicy and within an hour or two it’ll feel like a dance party in your belly as your budding baby burrito gets a hint of that enchilada. Savor some scampi, and your little shrimp will catch a wave of garlic.

Need another reason to add variety to your second and third trimester menus? Studies show that babies who have sampled certain foods while in utero are more inclined to eat them once they hit the high chair. So putting broccoli, carrots, and kale on your plate now packs a one-two punch: great nutrition for you and your baby, and a greater likelihood your potentially picky eater will savor those veggies later on.

At a Glance

She's Got the Moves

Your baby's arms and legs are in proportion this week and her movements are now much more coordinated. Also: notice a jump in baby's length this week? Up til now, we've been measuring from crown to rump, but now we start to measure from crown to heel, which explains why she suddenly "grew" so much.

More Blood Cells

Your baby-to-be's liver and spleen have been working hard producing blood cells, but now bone marrow spaces are mature enough to help as well.

Baby's Drinking

While the placenta is still #1 when it comes to nourishment, now your baby takes in small amounts of amniotic fluid, too.

Baby's Moving and Sleeping

How big is your baby? Switching from crown-to-rump to crown-to-heel length, she's 10-and-a-half inches long and weighs 11 to 12-and-a-half ounces, about the size of a large banana. Your developing baby still has a great deal of room in your womb — though like anyone who lives in one space for a long time, this tenant will soon begin to feel cramped. Until those uterine walls start closing in, however, there's plenty of space for twisting, turning and even an occasional somersault (so that's what you were feeling last night!). With all that belly dancing going on, it's hard to believe your baby is getting any shut-eye at all. But believe it or not, your fetus sleeps as much as a newborn. (Now if only you could get some sleep yourself!)

Baby's Taste Buds Develop

Speaking of carrots, if you eat one this week, there's a good chance your baby will taste it too. That's because when you're 21 weeks pregnant, your baby swallows a bit of amniotic fluid each day — not only for nutrition and hydration, but also to practice swallowing and digesting, skills he'll need as soon as he arrives in your arms. And keep this in mind: The taste of the amniotic fluid differs from day to day depending on what you've eaten (spicy enchilada one day, sweet banana the next). That smorgasbord of flavors won't be lost on your baby since your little one has very developed taste buds already. In fact, researchers have noted that babies who were exposed to certain tastes in utero via the amniotic fluid were more eager to eat foods with those same tastes after birth. Want your peanut to eat his broccoli later? Eat yours now!

Baby's Getting Coordinated

Your little action figure is able to choreograph Matrix-like moves at 21 weeks pregnant. Arms and legs are finally in proportion, neurons are now connected between the brain and muscles and cartilage throughout the body is turning to bone. All these upgrades combine to give your baby more control over limb movements, which explains all that kicking, stretching and bodysurfing (or rather bellysurfing) you may have started feeling.

Your Body at Week 21

Stretch Marks

At 21 weeks pregnant, your baby might be starting to leave his or her mark — in the form of stretch marks, that is — all over your stomach, butt, thighs, hips and breasts. These pink, red or purple streaks appear as your body expands and your tummy and breasts just keep on growing: The supporting tissue under your skin gets torn as the skin stretches. Only about one in two women gets them, though you're a likely candidate if your mom had stretch marks during her pregnancy. Darker-skinned women are less likely to get them (plus, they're not as visible on dark skin), while fair-skinned gals are usually less lucky. Rapid weight gain can also predispose you to getting stretch marks — another good reason to add your pounds slowly and steadily (at an average of about a pound a week these days).

Unfortunately, there's no proven way to prevent stretch marks from zigzagging their way across your body (though there's no harm in applying moisturizers like cocoa butter; if nothing else, it will prevent the dryness and itching associated with pregnancy-stretched skin). Is there any good news? Here's something: They won't stay so vividly hued forever. After delivery, they usually fade to a less noticeable silvery-gray color.

Relieving Anxiety

Now that you're starting to look pregnant (and not just like you were spending too much time with the Ben & Jerry's) and those kicks can no longer be mistaken for gas, the reality of pregnancy is probably beginning to sink in. And with it, you may find, a few ambivalent or anxious feelings you're even ambivalent about admitting (Me a mom? There must be some mistake!). Don't worry — and hang on. At some point in pregnancy (and usually once that pregnancy becomes a very visible reality) just about every expectant mother (and father!) begins to feel anxiety and fear as though she's on a runaway train — with enormous changes coming round the bend. And not only is it completely normal to feel anxious, it's especially healthy to acknowledge it. Talk your feelings over with your friends who've had babies — they’ll reassure you that they experienced the same kind of thoughts. Most important, discuss your fears with your partner, who's probably just as in need of a good heart-to-heart.

Pregnancy Symptoms Week 21

By now you may be able to feel your baby twisting, turning and kicking in the womb (though many new expectant moms mistake the feeling for gas). Enjoy these first gentle love taps — soon enough your growing baby’s kicks will get more aggressive. Read More

Are you always in the mood...to eat? Carry healthy snacks with you (such as nuts, raisins, trail mix or granola bars) so that you’ll have nutritious fuel to keep you and your baby-to-be nourished even when you’re on the go. Read More

The increasing pressure your uterus is placing on your rectum can mean that you’re having a hard time containing yourself (your gas, that is). Drink plenty of water and eat fiber-rich foods to avoid becoming constipated, which can make gassiness worse. Read More

Not only is your center of gravity shifting and putting extra strain on your back, but the hormone relaxin is also causing your ligaments and joints to stretch and loosen, which means additional achiness in your back. If you can, splurge for a prenatal massage from a trained professional. Read More

Have you noticed that your hair and nails are growing at record speed? Pregnancy hormones are partly the cause — as is the increased circulation in your body, bringing extra nutrients to your hair and nails (and to your baby, of course). Read More

Tips for You This Week

Choose Low-Impact Exercises

You should exercise, but keep it low-impact with swimming, yoga or walking. You’re more susceptible to injury right now thanks to ligament-loosening relaxin in your body.

Elevate Your Feet

Finding it harder to tie your shoes than usual? Swollen feet and ankles may be to blame. Because your body has about 50 percent more blood and fluid than it did pre-baby, these body parts may swell. So be sure to clock in a few sit-and-elevate sessions throughout the day.

Keep an Eye on the Scale

How much weight is too much? That all depends. Chances are your practitioner advised you on your target weight gain at your first prenatal appointment — and that it was calculated based on a number of factors (for starters, how close to ideal your pre-pregnancy weight was). Your practitioner probably also talks to you (ever so gently, or not so) at every visit about where you are on that upward curve — and where you should aim to be. If you've been instructed to gain the standard 25-to-35-pound total in your pregnancy, by this week you're likely to have gained anywhere from 10 to 16 of those pounds. If you raced past that number weeks ago, or are gaining faster than your practitioner recommended, you'll want to slow down.

Avoid Empty Calories

The emphasis is on "useless" (aka empty) — you still want to eat enough of the right kinds of calories to keep your baby fed and growing. After all, the idea isn't to lose weight (losing weight is always a bad idea when you're pregnant), but to slow the rate at which you're gaining. Easy, nutritious, calorie-reducing strategies (substituting skim milk for whole or 2 percent; fresh fruit for dried; baked potatoes or yams for french fries; grilled white-meat chicken with no skin for fried dark meat with skin) can make a big difference. Other calories that can go? The ones you'll find in sugar (and the ones you'll find plenty of in sugary treats).

Walk for 30 Minutes a Day

Is your plumbing clogged? Then start working out. Both during pregnancy and in those first postpartum weeks physical activity is one of the best ways to stimulate your bowels and fight constipation. Even just a half-hour walk a day can do the trick, especially if you drink plenty of water and favor fiber-rich foods (take some trail mix when you hit the trail).

Avoid Lasers

Your legs, armpits, bikini line and upper lip may be hairier than usual due to all those raging hormones. But think twice before you turn to lasers, electrolysis, depilatories and bleaching. No reliable studies have been done to determine for sure whether these popular hair-removal and lightening treatments are harmful or not, but it's probably best to skip them until after you give birth. Take heart, though, you may pluck or shave to your heart's content. (Even waxing is fine if your skin's not too sensitive.) That's not making you feel better? Chin up — you're more than halfway to the finish line!

Take Steps to Avoid Anemia

You might want to take an iron supplement. Although there are plenty of ways to get iron from the foods you eat, it's always good to have extra insurance when it comes to this vital nutrient. Taking a 30-to-50-mg iron supplement during the crucial second half of your pregnancy will ensure that you're getting what you and your baby need. (If your practitioner notes that your iron stores are particularly low, he or she may recommend a higher-dosage supplement.) You should also eat your spinach. If spinach isn't appealing (though think out of the can here — you can also serve spinach up fresh in a salad, wilted under seared fish or grilled meat or sauteed with pasta and cheese), there are lots of other iron-rich foods you can pump your diet up with, including lean beef, sardines, cooked clams, oysters, mussels and shrimp, cooked dried beans, dried fruit, oat bran, Jerusalem artichokes and seaweed. Finally, keep your caffeine down. Caffeine may perk you up, but it dashes the effects of iron. If you wash down that iron-rich steak with a cola (or that bag of trail mix with a coffee), you're reducing the amount of iron that gets absorbed into your system.

Updated: May 13, 2019

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You’re Expecting. Health information on this site is based on peer-reviewed medical journals and highly respected health organizations and institutions including ACOG (American College of Obstetricians and Gynecologists), CDC (Centers for Disease Control and Prevention) and AAP (American Academy of Pediatrics), as well as the What to Expect books by Heidi Murkoff.

Recommended Products

Just so you know, What to Expect may earn commissions from the shopping links included on this page.